Alzheimer's disease is a progressive, neurodegenerative disease characterized in the brain by abnormal clumps (amyloid plaques) and tangled bundles of fibers (neurofibrillary tangles) composed of misplaced proteins. Age is the most important risk factor for Alzheimer's disease. The number of people with the disease doubles every 5 years beyond age 65. Three genes have been discovered that cause early onset (or family) Alzheimer's. Other genetic mutations that cause excessive accumulation of amyloid protein are associated with age-related (sporadic) Alzheimer's.

Symptoms of Alzheimer's disease include memory loss, language deterioration, impaired ability to mentally manipulate visual information, poor judgment, confusion, restlessness, and mood swings. Eventually Alzheimer's destroys cognition, personality, and the ability to function. The early symptoms of Alzheimer's disease, which include forgetfulness and loss of concentration, are often missed because they resemble natural signs of aging.

In the Alzheimer's Series:

• An Introduction to Alzheimer's
• Symptoms of Alzheimer's
• Causes of Alzheimer's
• How Alzheimer's is Diagnosed
• Treatment of Alzheimer's
• Alzheimer's Care and Planning for Families
• What is the Outlook for Alzheimer's?
• Further Information

Last reviewed: By John M. Grohol, Psy.D. on 12 Nov 2008